| 摘要 |
The present invention provides a hydraulic brake piston adjuster assembly (10) that includes a first or outer piston (30) housing and a second inner piston (40). The first piston (30) has a first piston end (31) received within a housing bore (16) and the end (31) extends axially to include an inlet (32) having a relief valve mechanism (34). The second piston (40)includes an axially inner second piston end (42) received within the bore (36) of the first piston (30) and extends axially to encompass the inlet (32) of the first piston (30) and so that the piston ends (31, 42) define therebetween an inner piston chamber (50). A first piston second end abuts a running clearance adjustment mechanism (59) comprising an axially displaceable collar member (60). When hydraulic brake pressure is received within a piston housing chamber (17) of the housing bore (16), the first and second pistons (30, 40) are displaced axially outwardly of the housing bore (16) such that the collar member (60)is displaced with the first piston (30) and takes up a clearance (X). After the clearance (X) is taken up, hydraulic pressure opens the relief valve mechanism (34) to permit fluid flow into the inner piston chamber (50) and displace the second piston (40) relative to the first piston (30). Because the relief valve mechanism (34) is a unidirectional valve (34), hydraulic fluid is trapped within the inner piston chamber (50) to attain an adjusted position of the second piston (40) relative to the first piston (30). |
